group_intersection.c

刚才是说明 现在是安装程序在 LINUX环境下进行编程的MPICH安装文件

/* -*- Mode: C; c-basic-offset:4 ; -*- */
/*
 *
 *  (C) 2001 by Argonne National Laboratory.
 *      See COPYRIGHT in top-level directory.
 */

#include "mpiimpl.h"
#include "group.h"

/* -- Begin Profiling Symbol Block for routine MPI_Group_intersection */
#if defined(HAVE_PRAGMA_WEAK)
#pragma weak MPI_Group_intersection = PMPI_Group_intersection
#elif defined(HAVE_PRAGMA_HP_SEC_DEF)
#pragma _HP_SECONDARY_DEF PMPI_Group_intersection  MPI_Group_intersection
#elif defined(HAVE_PRAGMA_CRI_DUP)
#pragma _CRI duplicate MPI_Group_intersection as PMPI_Group_intersection
#endif
/* -- End Profiling Symbol Block */

/* Define MPICH_MPI_FROM_PMPI if weak symbols are not supported to build
   the MPI routines */
#ifndef MPICH_MPI_FROM_PMPI
#define MPI_Group_intersection PMPI_Group_intersection

#endif

#undef FUNCNAME
#define FUNCNAME MPI_Group_intersection

/*@
   MPI_Group_intersection - intersection of two groups

   Arguments:
+  MPI_Group group1 - group1
.  MPI_Group group2 - group2
-  MPI_Group *newgroup - new group

   Notes:

.N Fortran

.N Errors
.N MPI_SUCCESS
@*/
int MPI_Group_intersection(MPI_Group group1, MPI_Group group2, MPI_Group *newgroup)
{
    static const char FCNAME[] = "MPI_Group_intersection";
    int mpi_errno = MPI_SUCCESS;
    MPID_Group *group_ptr1 = NULL;
    MPID_Group *group_ptr2 = NULL;
    MPID_Group *new_group_ptr;
    int size1, size2, i, k, g1_idx, g2_idx, l1_pid, l2_pid, nnew;
    MPID_MPI_STATE_DECL(MPID_STATE_MPI_GROUP_INTERSECTION);

    MPID_MPI_FUNC_ENTER(MPID_STATE_MPI_GROUP_INTERSECTION);
    /* Get handles to MPI objects. */
    MPID_Group_get_ptr( group1, group_ptr1 );
    MPID_Group_get_ptr( group2, group_ptr2 );
#   ifdef HAVE_ERROR_CHECKING
    {
        MPID_BEGIN_ERROR_CHECKS;
        {
	    MPIR_ERRTEST_INITIALIZED(mpi_errno);
            /* Validate group_ptr */
            MPID_Group_valid_ptr( group_ptr1, mpi_errno );
            MPID_Group_valid_ptr( group_ptr2, mpi_errno );
	    /* If either group_ptr is not valid, it will be reset to null */
            if (mpi_errno) {
                MPID_MPI_FUNC_EXIT(MPID_STATE_MPI_GROUP_INTERSECTION);
                return MPIR_Err_return_comm( 0, FCNAME, mpi_errno );
            }
        }
        MPID_END_ERROR_CHECKS;
    }
#   endif /* HAVE_ERROR_CHECKING */

    /* ... body of routine ...  */
    /* Return a group consisting of the members of group1 that are 
       in group2 */
    size1 = group_ptr1->size;
    size2 = group_ptr2->size;
    /* Insure that the lpid lists are setup */
    MPIR_Group_setup_lpid_pairs( group_ptr1, group_ptr2 );

    /* We must lock against other threads while using the flag array */
    MPID_Common_thread_lock();
    {
	for (i=0; i<size1; i++) {
	    group_ptr1->lrank_to_lpid[i].flag = 0;
	}
	g1_idx = group_ptr1->idx_of_first_lpid;
	g2_idx = group_ptr2->idx_of_first_lpid;
	
	nnew = 0;
	while (g1_idx >= 0 && g2_idx >= 0) {
	    l1_pid = group_ptr1->lrank_to_lpid[g1_idx].lpid;
	    l2_pid = group_ptr2->lrank_to_lpid[g2_idx].lpid;
	    if (l1_pid < l2_pid) {
		g1_idx = group_ptr1->lrank_to_lpid[g1_idx].next_lpid;
	    }
	    else if (l1_pid > l2_pid) {
		g2_idx = group_ptr2->lrank_to_lpid[g2_idx].next_lpid;
	    }
	    else {
		/* Equal */
		group_ptr1->lrank_to_lpid[g1_idx].flag = 1;
		g1_idx = group_ptr1->lrank_to_lpid[g1_idx].next_lpid;
		g2_idx = group_ptr2->lrank_to_lpid[g2_idx].next_lpid;
		nnew ++;
	    }
	}
	/* Create the group.  Handle the trivial case first */
	if (nnew == 0) {
	    *newgroup = MPI_GROUP_EMPTY;
	    MPID_Common_thread_unlock();
	    MPID_MPI_FUNC_EXIT(MPID_STATE_MPI_GROUP_INTERSECTION);
	    return MPI_SUCCESS;
	}
	
	mpi_errno = MPIR_Group_create( nnew, &new_group_ptr );
	if (mpi_errno) {
	    MPID_Common_thread_unlock();
	    MPID_MPI_FUNC_EXIT(MPID_STATE_MPI_GROUP_INTERSECTION);
	    return MPIR_Err_return_comm( 0, FCNAME, mpi_errno );
	}
	new_group_ptr->rank = MPI_UNDEFINED;
	k = 0;
	for (i=0; i<size1; i++) {
	    if (group_ptr1->lrank_to_lpid[i].flag) {
		new_group_ptr->lrank_to_lpid[k].lrank = k;
		new_group_ptr->lrank_to_lpid[k].lpid = 
		    group_ptr1->lrank_to_lpid[i].lpid;
		if (i == group_ptr1->rank) 
		    new_group_ptr->rank = k;
		k++;
	    }
	}
    }
    MPID_Common_thread_unlock();

    *newgroup = new_group_ptr->handle;

    /* ... end of body of routine ... */
    MPID_MPI_FUNC_EXIT(MPID_STATE_MPI_GROUP_INTERSECTION);
    return MPI_SUCCESS;
}